Field
The present application relates generally to wireless communications, and more specifically to methods and apparatuses for selecting enhanced distributed channel access (EDCA) parameters for multi-user (MU) transmissions.
Background
Communications networks are used to exchange messages among devices. Wireless networks are often preferred when the network elements are mobile and thus have dynamic connectivity needs, or if the network architecture is formed in an ad hoc, rather than fixed, topology. The devices in a wireless network may transmit/receive information based on channel access protocols such as enhanced distributed channel access (EDCA). EDCA defines separate data traffic access categories, which may include best effort, background, video and voice over wireless local access network (WLAN) (VoWLAN). For example, data traffic associated with transmission or reception of emails may be assigned a low priority class, and VoWLAN may be assigned a high priority class. Utilizing EDCA, high-priority data traffic has more opportunity of being sent than a low-priority data traffic because a station with high priority data traffic waits for less time before sending such a data packet, on average, than a station with low priority data traffic.
Wireless networks are often preferred when the network elements are mobile and thus have dynamic connectivity needs, or if the network architecture is formed in an ad hoc, rather than fixed, topology. Wireless networks employ intangible physical media in an unguided propagation mode using electromagnetic waves in the radio, microwave, infrared, optical, etc. frequency bands. Wireless networks advantageously facilitate user mobility and rapid field deployment when compared to fixed wired networks.
In order to address the issue of increasing bandwidth requirements that are demanded for wireless communications systems, different schemes are being developed to allow multiple user terminals (UTs) to communicate with a single access point by sharing the channel resources while achieving high data throughputs. With limited communication resources, it is desirable to reduce the amount of traffic passing between the access point and the multiple terminals. For example, when multiple terminals send uplink communications to the access point, it is desirable to minimize the amount of traffic to complete the uplink of all transmissions. Thus, there is a need for an improved protocol for uplink transmissions from multiple terminals.